A Balanced Dithering Technique
By Thiadmer Riemersma, December 01, 1998
Dithering with just one neighbor doesn't sound very helpful - unless you're clever about how you visit the neighbors.
December 1998/A Balanced Dithering Technique/Listing 2
enum {
UP,
LEFT,
DOWN,
RIGHT,
};
void hilbert(int level,int direction=UP)
{
if (level==1) {
switch (direction) {
/* move() could draw a line in... */
/* ...the indicated direction */
case LEFT:
move(RIGHT);
move(DOWN);
move(LEFT);
break;
case RIGHT:
move(LEFT);
move(UP);
move(RIGHT);
break;
case UP:
move(DOWN);
move(RIGHT);
move(UP);
break;
case DOWN:
move(UP);
move(LEFT);
move(DOWN);
break;
} /* switch */
} else {
switch (direction) {
case LEFT:
hilbert_level(level-1,UP);
move(RIGHT);
hilbert_level(level-1,LEFT);
move(DOWN);
hilbert_level(level-1,LEFT);
move(LEFT);
hilbert_level(level-1,DOWN);
break;
case RIGHT:
hilbert_level(level-1,DOWN);
move(LEFT);
hilbert_level(level-1,RIGHT);
move(UP);
hilbert_level(level-1,RIGHT);
move(RIGHT);
hilbert_level(level-1,UP);
break;
case UP:
hilbert_level(level-1,LEFT);
move(DOWN);
hilbert_level(level-1,UP);
move(RIGHT);
hilbert_level(level-1,UP);
move(UP);
hilbert_level(level-1,RIGHT);
break;
case DOWN:
hilbert_level(level-1,RIGHT);
move(UP);
hilbert_level(level-1,DOWN);
move(LEFT);
hilbert_level(level-1,DOWN);
move(DOWN);
hilbert_level(level-1,LEFT);
break;
} /* switch */
} /* if */
}
/* End of File */
